Git-Mirrors/OpenModem
1
0
Fork 0
mirror of https://github.com/markqvist/OpenModem.git synced 2025-05-15 21:02:29 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

Filters reworked for new samplerate

Browse source
This commit is contained in:
Mark Qvist 2018-12-30 00:32:19 +01:00
parent 74e0b0d1db
commit 56bed68143
4 changed files with 69 additions and 57 deletions
Download patch file Download diff file Expand all files Collapse all files

29
hardware/AFSK.h
View file

@ -35,9 +35,11 @@ inline static uint8_t sinSample(uint16_t i) {
#define BITS_DIFFER(bits1, bits2) (((bits1)^(bits2)) & 0x01)
#define TRANSITION_FOUND(bits) BITS_DIFFER((bits), (bits) >> 1)
// TODO: Maybe expand number of bits looked at here:
// TODO: Maybe revert to only looking at two samples
#define DUAL_XOR(bits1, bits2) ((((bits1)^(bits2)) & 0x03) == 0x03)
#define SIGNAL_TRANSITIONED(bits) DUAL_XOR((bits), (bits) >> 2)
#define QUAD_XOR(bits1, bits2) ((((bits1)^(bits2)) & 0x0F) == 0x0F)
#define SIGNAL_TRANSITIONED(bits) QUAD_XOR((bits), (bits) >> 4)
// #define SIGNAL_TRANSITIONED(bits) DUAL_XOR((bits), (bits) >> 2)
#define CPU_FREQ F_CPU
@ -53,16 +55,19 @@ inline static uint8_t sinSample(uint16_t i) {
#define SAMPLESPERBIT (CONFIG_SAMPLERATE / BITRATE)
#define TICKS_BETWEEN_SAMPLES ((((CPU_FREQ+FREQUENCY_CORRECTION)) / CONFIG_SAMPLERATE) - 1)
// TODO: Calculate based on sample rate
#define PHASE_INC SAMPLESPERBIT/8 // Nudge by an eigth of a sample each adjustment
#define PHASE_BITS 8 // How much to increment phase counter each sample
// TODO: Calculate based on sample rate [Done?]
#define PHASE_BITS 8 // 8 // Sub-sample phase counter resolution
#define PHASE_INC 1 // 1 // Nudge by above resolution for each adjustment
#define PHASE_MAX (SAMPLESPERBIT * PHASE_BITS) // Resolution of our phase counter
#define PHASE_THRESHOLD (PHASE_MAX / 2) // Target transition point of our phase window
#define PHASE_MAX (SAMPLESPERBIT * PHASE_BITS) // 128 // Size of our phase counter
// TODO: Test which target is best in real world
#define PHASE_THRESHOLD (PHASE_MAX / 2)+3*PHASE_BITS // Target transition point of our phase window
//#define PHASE_THRESHOLD (PHASE_MAX / 2) // 64 // Target transition point of our phase window
#define DCD_TIMEOUT_SAMPLES CONFIG_SAMPLERATE/100
#define DCD_MIN_COUNT CONFIG_SAMPLERATE/1600
// TODO: Revamp filtering
#if BITRATE == 1200
#define FILTER_CUTOFF 600
#define MARK_FREQ 1200
@ -120,8 +125,12 @@ typedef struct Afsk
int16_t iirX[2]; // IIR Filter X cells
int16_t iirY[2]; // IIR Filter Y cells
uint8_t sampledBits; // Bits sampled by the demodulator (at ADC speed)
int8_t currentPhase; // Current phase of the demodulator
#if SAMPLESPERBIT < 17
uint16_t sampledBits; // Bits sampled by the demodulator (at ADC speed)
#else
#error Not enough space in sampledBits variable!
#endif
int16_t currentPhase; // Current phase of the demodulator
uint8_t actualBits; // Actual found bits at correct bitrate
volatile int status; // Status of the modem, 0 means OK